Abstract: A reception frequency band is selected at 11.7 GHz–12.2 GHz, the local oscillating frequencies of local oscillators are determined at 10.75 GHz and 13.85 GHz, respectively, and each intermediate frequency band is selected at 950 MHz–1450 MHz and 1650 MHz–2150 MHz, respectively, so that the harmonic component of the frequency difference between local oscillation signals output from each local oscillator is not present in the frequency band of each intermediate frequency signal output from each mixer and in the reception band of polarization signals applied to input terminals.

Abstract: An MMIC (Microwave Monolithic Integrated Circuit)-mounted substrate includes a double-metal-foil dielectric substrate having a dielectric substrate with a metal foil pattern formed on both sides of the substrate, an MMIC that is a surface-mount high power amplifier mounted on one side of the double-metal-foil dielectric substrate, and a metal chassis attached to the other side of the double-metal-foil dielectric substrate. The double-metal-foil dielectric substrate has a plurality of through holes. A copper foil pattern that is a metal foil pattern continuously extends to cover the inner surfaces of the through holes and both sides of the dielectric substrate, and solder is buried in the through holes.

Abstract: An LNB (low noise block down converter) that can have a plurality of receivers connected includes a conversion unit receiving a plurality of types of polarized wave signals transmitted from each of a plurality of satellites to convert the plurality of polarized wave signals into a plurality of intermediate frequency signals, an amplify switch connected to the conversion unit to receive the plurality of intermediate frequency signals as inputs, and having a plurality of outputs connected to a plurality of output ports, respectively, determining a status according to a select signal and providing an amplified intermediate frequency signal, and a first control unit receiving digital serial data to select a satellite from an external source via an output port and providing a select signal according to the digital serial data.

Abstract: A plurality of composite elements are arranged in parallel with each other on a substrate. The composite elements each include a rectangular microstrip line element, an input microstrip line and an output microstrip line. The microstrip line element has one longer side, the other longer side, one end and the other end, and the input microstrip line is connected at the one end to the one longer side while the output microstrip line is connected at the other end to the other longer side. The composite elements are cascaded to constitute a low-pass filter.

Abstract: A reception frequency band is selected at 11.7 GHz-12.2 GHz, the local oscillating frequencies of local oscillators are determined at 10.75 GHz and 13.85 GHz, respectively, and each intermediate frequency band is selected at 950 MHz-1450 MHz and 1650 MHz-2150 MHz, respectively, so that the harmonic component of the frequency difference between local oscillation signals output from each local oscillator is not present in the frequency band of each intermediate frequency signal output from each mixer and in the reception band of polarization signals applied to input terminals.

Abstract: A plurality of composite elements are arranged in parallel with each other on a substrate. The composite elements each include a rectangular microstrip line element, an input microstrip line and an output microstrip line. The microstrip line element has one longer side, the other longer side, one end and the other end, and the input microstrip line is connected at the one end to the one longer side while the output microstrip line is connected at the other end to the other longer side. The composite elements are cascaded to constitute a low-pass filter.

Abstract: A horizontally polarized wave signal is amplified in low-noise by two first LNAs connected in series to each other. The resulting low-noise amplified signal is entered into a first high electron mobility transistor mixer via a first band-pass filter. The first high electron mobility transistor mixer converts the signal into an intermediate frequency signal based on local power fed from a local oscillator via a Y-type distribution circuit and a first directional filter, and provides the converted signal as an output thereof. Meanwhile, a vertically polarized wave signal is amplified in low-noise by two second LNAs connected in series to each other. The resulting low-noise amplified signal is entered into a second high electron mobility transistor mixer via a second band-pass filter.

Abstract: One frame of speech signal data and subframes of speech signal data divided from the frame of speech signal data are encoded by frame and subframe encoding processes while another frame is decoded by frame and subframe decoding processes. The frame and subframe encoding processes and the frame and subframe decoding processes are interleaved to reduce the DSP memory capacity needed for a speech codec.

Abstract: A speech encoder synthesizes an excitation sound source in accordance with the linear coupling of at least two predetermined basis vectors. In realizing the codebook search by using signal processing LSIs, the ordination of the first cross correlation R.sub.m between an input speech signal p(n) and plural reproduced signals obtained by using plural basis vectors is computed, and the ordination of the second cross correlation D.sub.mj of the plural reproduced signals qm(n) is computed. These ordinations are arranged to be one ordination Rd.sub.mj. By using the ordination Rd.sub.mj, all possible combinations of the third and fourth cross correlation calculations are carried out to provide a most optimum codebook.

Abstract: A microwave oscillation circuit unit to be installed on one surface of a chassis base having a circuit substrate on its other surface. The unit is provided with at least two screws, and a power supply terminal and an output terminal on its one surface confronting the chassis base when installed on the chassis base. In such a structure, a first nut is threaded on one of the screws which is positioned adjacent to the power supply terminal and the output terminal so that torque caused by tightening the first nut to such one of the screws may act upon the chassis base, the first nut being clear from the circuit substrate. Furthermore, a second nut is threaded on the other of the screws which is positioned apart from both the terminals so that torque caused by tightening the second nut to the other of the screws acts upon both the chassis base and the circuit substrate.

Abstract: In a 1/2 wavelength side coupling filter, a plurality of resonance lines (4) are arranged on a board (20) in parallel to each other in a staggered manner so that respective ends thereof have step portions. An input coupling line (3) is arranged in parallel to the plurality of resonance lines, with an input end (5) formed opposed to an intermediate position of the adjacent resonance line and one end portion (6) formed aligned with one end portion of the adjacent resonance line. An adjusting line (7) is formed extending from one end portion (6) on the input coupling line, and the filtering characteristics adjusted by the adjusting line.

Abstract: A lower-noise microwave amplifying circuit for use in a lower-noise converter includes a metallic conductor for use in performance adjustment. The metallic conductor projects from the microstrip line and is provided near a bendable connecting portion between an input coaxial rod in a coaxial waveguide conversion portion and a microstrip line for constructing one portion of an amplifying circuit. Therefore, the lower-noise microwave amplification circuit is easily adjusted for improving the basic characteristics such as input VSWR or the like and is simpler in construction.